A service provider network typically comprises a number of different types of computer networks interconnected to one another. One type of network referred to as an access network enables host devices, which may also be referred to as subscriber devices or customer premises equipment (CPE), to access the service provider network via subscriber lines. Subscriber devices or CPE may comprise set-top boxes (STBs), laptop computers, desktop computers, mobile devices (such as mobile cellular phones and so-called “smart phones”), Voice over Internet Protocol (VoIP) telephones, workstations, modems, wireless access points (WAPs), gaming consoles, and other devices capable of accessing or otherwise facilitating access to the service provider network.
The access network typically comprises a number of access nodes, such as a Digital Line Subscriber Line Access Multiplexer (DSLAM) or a Cable Modem Termination System (CMTS), that each manages access by one or more of the subscriber devices to the service provider network. The access node may, for example, multiplex (or “aggregate”) traffic from subscriber devices into a composite signal and transmit this signal upstream to the subscriber network for delivery to one or more destinations.
In addition to access nodes, the access network typically comprises one or more Open Systems Interconnection (OSI) layer two switches that connect subscriber devices to an OSI layer three device, e.g., an access router. A layer two switch may be configured to switch network traffic toward an access node using the media access control (MAC) address of the subscriber device. The access node also uses the MAC address in order to direct the network traffic to the correct host device. Both the access node and the switch maintain tables, e.g., bridging tables, that map the physical ports on the access node or switch to the destination MAC addresses of the subscriber devices. In this manner, the access node or the switch is able to determine which of their respective ports should be selected to send traffic to a specific subscriber device.